A conventional engine intake air amount control apparatus disclosed, for instance, by Patent Document 1 includes a control mechanism for varying the valve timing of an intake valve and a control mechanism for varying the opening of a throttle valve. When controlling the intake air amount, the technology incorporated in the above conventional control apparatus avoids a torque difference from being generated by a sudden accelerator pedal operation by providing a response delay correction not only for the above valve timing control but also for throttle valve opening control.
Another known technology disclosed, for instance, by Patent Document 2 flows an exhaust gas back into a combustion chamber while fuel is cut off at the time of deceleration. A catalyst positioned in an exhaust path of an internal combustion engine is likely to deteriorate when a lean gas supply is received in a high-temperature environment. The technology disclosed by Patent Document 2 can prevent the catalyst from deteriorating because it can inhibit a lean, high-temperature gas from being supplied to the catalyst while fuel is cut off at the time of deceleration.
The applicant of the present invention has acknowledged that the following documents relate to the present invention including the aforementioned documents:
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-159355
[Patent Document 2]
Japanese Patent Laid-Open No. 1997-209844
[Patent Document 3]
Japanese Patent Laid-Open No. 1998-9005
[Patent Document 4]
Japanese Patent Laid-Open No. 1999-351044
[Patent Document 5]
Japanese Patent Laid-Open No. 1999-107839
[Patent Document 6]
Japanese Patent Laid-Open No. 2004-183615